re PR c++/69850 (unnecessary -Wnonnull-compare warning)

	PR c++/69850
	* rtti.c (ifnonnull): Set TREE_NO_WARNING on the condition, use
	NE_EXPR instead of EQ_EXPR and swap last two arguments on COND_EXPR.

	* g++.dg/warn/Wnonnull-compare-4.C: New test.

From-SVN: r233568

gcc/cp/ChangeLog

+2016-02-19  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/69850
+	* rtti.c (ifnonnull): Set TREE_NO_WARNING on the condition, use
+	NE_EXPR instead of EQ_EXPR and swap last two arguments on COND_EXPR.
+
 2016-02-19  Patrick Palka  <ppalka@gcc.gnu.org>
 
 	PR c++/68948

gcc/cp/rtti.c

@@ -507,12 +507,13 @@ get_typeid (tree type, tsubst_flags_t complain)
 static tree
 ifnonnull (tree test, tree result, tsubst_flags_t complain)
 {
-  return build3 (COND_EXPR, TREE_TYPE (result),
-		 build2 (EQ_EXPR, boolean_type_node, test,
-			 cp_convert (TREE_TYPE (test), nullptr_node,
-				     complain)),
-		 cp_convert (TREE_TYPE (result), nullptr_node, complain),
-		 result);
+  tree cond = build2 (NE_EXPR, boolean_type_node, test,
+		      cp_convert (TREE_TYPE (test), nullptr_node, complain));
+  /* This is a compiler generated comparison, don't emit
+     e.g. -Wnonnull-compare warning for it.  */
+  TREE_NO_WARNING (cond) = 1;
+  return build3 (COND_EXPR, TREE_TYPE (result), cond, result,
+		 cp_convert (TREE_TYPE (result), nullptr_node, complain));
 }
 
 /* Execute a dynamic cast, as described in section 5.2.6 of the 9/93 working

gcc/testsuite/ChangeLog

 2016-02-19  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/69850
+	* g++.dg/warn/Wnonnull-compare-4.C: New test.
+
 	PR c++/69851
 	* g++.dg/torture/pr69851.C: New test.
 

gcc/testsuite/g++.dg/warn/Wnonnull-compare-4.C

+// PR c++/69850
+// { dg-do compile }
+// { dg-options "-Wnonnull-compare" }
+
+struct A { virtual ~A (); int foo (); };
+struct B { virtual ~B () { } };
+struct C : B, A { };
+
+int
+A::foo ()
+{
+  C *c = dynamic_cast<C *> (this);	// { dg-bogus "nonnull argument" }
+  return !c;
+}